Plant care
Sea Mouse-eartemperature & humidity
Cerastium diffusum
More about sea mouse-ear
Ideal temperature for sea mouse-ear
Temperature kills fewer sea mouse-ear plants than you'd think. What kills them is the micro-climate within a normal-temperature room — a leaf pressed against single-glazed winter glass, the hot dry updraft directly above a radiator, the cold blast from an AC vent. The thermostat reading at 0–20°C (32–68°F) is fine; the spot you put the plant in matters more. Below roughly 0°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Sea Mouse-ear is comparatively hardy (USDA 5-9, RHS H5). Within that range it tolerates a cold dormant spell outdoors; outside it, grow it in a container you can move under cover or overwinter in a cool but frost-free spot. Hardiness assumes an established plant in well-drained soil — a wet, cold root zone kills far more plants than cold air alone.
Humidity for sea mouse-ear
Sea Mouse-ear sits happiest at around Low (coastal ambient) relative humidity. Adapted to exposed, wind-dried coastal air; high ambient humidity combined with still conditions encourages fungal lesions on the delicate stems. The usual low-humidity tell is crisp brown leaf tips and edges while the soil moisture is fine — a sign the air, not the watering, is the problem. If you need to raise it, the reliable methods are grouping plants together, standing the pot on a tray of damp pebbles (the pot above the waterline, never in it), or running a small humidifier in winter when indoor heating dries the air most. Misting is the least effective — it raises humidity for minutes, not hours.
Sea Mouse-ear temperature & humidity — frequently asked questions
What temperature is best for sea mouse-ear?
Sea Mouse-ear grows best between 0–20°C (32–68°F). Keep it out of cold draughts, off freezing windowsills in winter, and away from the hot dry air directly above radiators — the extremes matter far more than the average room temperature.
How cold can sea mouse-ear tolerate?
Sea Mouse-ear starts to suffer below roughly 0°C. It tolerates a cold dormant period within USDA 5-9, but a wet cold root zone is more dangerous than cold air.
What humidity does sea mouse-ear need?
Sea Mouse-ear prefers about Low (coastal ambient) relative humidity. Adapted to exposed, wind-dried coastal air; high ambient humidity combined with still conditions encourages fungal lesions on the delicate stems.
How do I raise humidity for sea mouse-ear?
Group it with other plants, stand the pot on a tray of damp pebbles (kept above the waterline), or run a small humidifier in winter. Misting only helps for a few minutes, so it is the weakest option for a plant that genuinely needs more humidity.
Can sea mouse-ear live outside?
Sea Mouse-ear is rated for USDA zone 5-9 and RHS hardiness H5. Within that range it can stay outdoors; outside it, grow it in a moveable container and protect the roots from a wet, cold winter.
More sea mouse-ear care
In the UK? Keeping sea mouse-ear warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full sea mouse-ear care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.